In silver halide photographic materials, photographic emulsion layers or other layers are often colored to allow light in a specific wavelength region to be absorbed.
A colored layer is provided between a photographic emulsion layer and a support or on the surface of the support which is opposite to the photographic emulsion layer, to prevent fuzz, that is, halation, from being caused by light scattered when incident light passes through photographic emulsion layers. A colored layer is also provided to prevent halation which occurs when incident light is reflected at the interface between the emulsion layer and the support or on the surface of the support which is opposite to the emulsion layer, and the reflected light enters the photographic emulsion layers again. Such a colored layer is called an antihalation layer.
In X-ray photographic materials, a colored layer is sometimes provided to improve sharpness, which functions as a cross-over cut filter which reduces cross-over light.
The layers to be colored generally comprise hydrophilic colloid. Dyes are generally incorporated in the layers to color them. It is necessary that the dyes meet the following requirements.
(1) The dyes have proper spectral absorption according to use.
(2) The dyes are inactive photographically and chemically. Namely, the dyes do not have any adverse effect on the performance of silver halide photographic emulsion layers in a chemical sense. For example, they do not cause a lowering in sensitivity, the degradation of latent images, or fogging.
(3) The dyes are decolorized or removed by dissolution during the course of processing, and any harmful color is not left on the photographic materials after processing.
However, when a colored layer such as an antihalation layer or a cross-over cut layer is formed by using hydrophilic colloid, the volume of the water-permeable layers increases, and as a result, drying characteristics during development deteriorate.
In order to solve this problem, studies have been conducted to fix dyes into a layer which is used to improve the adhesion between the hydrophilic colloid layer and the support. (The layer which plays a role in bonding the support to the hydrophilic colloid layer is referred to herein as the undercoat layer). Methods for fixing dyes into the undercoat layer include a method wherein a dye is allowed to be adsorbed by a mordant as described in Japanese Patent Application No. 62-224447, and U.S. Pat. Nos. 4,957,856 and 4,965,180, a method wherein a dye dissolved in oil as oil droplets is emulsified and dispersed as described in Japanese Patent Application No. 1-142688, a method wherein a dye is adsorbed on the surface of an inorganic material as described in Japanese Patent Application No. 1-139691, a method wherein a dye is adsorbed by a polymer as described in Japanese Patent Application No. 1-119851 and a method wherein a dye in the form of a solid is dispersed as described in Japanese Patent Application No. 1- 87637, and U.S. Pat. Nos. 4,803,150 and 4,900,652. The examples in these patent specifications disclose that an undercoating polymer layer and a dye layer are coated in such a form that they are adjacent to each other.
Such a coating form has a disadvantage in that the dye is introduced into the undercoating polymer and is left as a residual color after development.
It is believed that the dye enters into the gaps of the undercoating polymer and is confined in the polymer during the drying of the dye layer, whereby the residual color is formed.